TITLE:
Low Environmental Load Process for the Beckmann Rearrangement of Cycloalkanone Oximes by Brønsted Acid Catalyst with Cobalt Salts
AUTHORS:
Hidetoshi Yamamoto, Masahiro Komeda, Ayana Ozaki, Michinori Sumimoto, Kenji Hori, Tsunemi Sugimoto
KEYWORDS:
Beckmann Rearrangement, Cycloalkanone Oximes, Lactam, Cobalt Catalysts, Brønsted Acids
JOURNAL NAME:
International Journal of Organic Chemistry,
Vol.5 No.3,
August
21,
2015
ABSTRACT: Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amount of undesirable byproducts under mild reaction conditions, a low environmental load process was developed. Beckmann rearrangements of cyclohexanone oxime and cyclooctanone oxime were achieved using a combination of a Bronsted acid and cobalt tetra-fluoroborate hexahydrate. Various Bronsted acid catalysts (10 - 20 mol%) were used to obtain the corresponding lactams in high yields at 80℃.